1. Field of the Invention
This invention relates to a radiation image read-out apparatus comprising a read-out section, an erasing section and a stacking section combined integrally with each other for use in a radiation image recording and reproducing system.
2. Description of the Prior Art
When certain kinds of phosphors are exposed to a radiation such as X-rays, .alpha.-rays, .beta.-rays. .gamma.-rays, cathode rays or ultraviolet rays, they store a part of the energy of the radiation. Then, when the phosphor which has been exposed to the radiation is exposed to stimulating rays such as visible light, light is emitted by the phosphor in proportion to the stored energy of the radiation. A phosphor exhibiting such properties is referred to as a stimulable phosphor.
As disclosed in U.S. Pat. Nos. 4,258,264, 4,276,473, 4,315,318 and 4,387,428, and Japanese Unexamined patent Publication No. 56(1981)-11395, it has been proposed to use a stimulable phosphor in a radiation image recording and reproducing system. Specifically, a sheet provided with a layer of the stimulable phosphor (hereinafter referred to as a stimulable phosphor sheet) is first exposed to a radiation passing through an object to have a radiation image stored therein, and is then scanned with stimulating rays such as a laser beam which cause it to emit light in the pattern of the stored image. The light emitted by the stimulable phosphor sheet upon stimulation thereof is photoelectrically detected and converted to an electric image signal, which is processed as desired to reproduce a visible image on a recording medium such as a photographic film or on a display device such as a cathode ray tube (CRT).
In the aforesaid radiation image recording and reproducing system, the stimulable phosphor sheet is used to temporarily store a radiation image until it is read out by scanning with stimulating rays. Therefore, after the read-out of the radiation image is finished, the radiation energy remaining on the stimulable phosphor sheet should preferably be erased for reusing the stimulable phosphor sheet for image recording.
FIG. 3 is a schematic side view showing the conventional radiation image read-out apparatus proposed to satisfy the aforesaid need.
The radiation image read-out apparatus of FIG. 3 is provided with a read-out section 2 for reading out a radiation image stored in a stimulable phosphor sheet 1, an erasing section 3 for erasing the radiation energy remaining on the sheet 1 after image read-out, a stacking section 4 for stacking the sheets 1 after erasing, and a control unit 5 for controlling the operations of the read-out section 2, erasing section 3, stacking section 4 and the sheet conveyance system linking these sections.
The control unit 5 is positioned above the read-out section 2, and the erasing section 3 and the stacking section 4 are positioned at the side of the read-out section 2. The stimulable phosphor sheet 1 is conveyed to the read-out section 2 in the direction as indicated by the arrow A, and the radiation image stored in the sheet 1 is read out while it is conveyed by a conveyance means 6 constituted by rollers and belt conveyors in the direction as indicated by the arrow A1. After the image read-out is finished, the sheet 1 is further conveyed in the direction as indicated by the arrow A2 to the erasing section 3 where the sheet 1 is exposed to erasing light, for example, and the radiation energy remaining on the sheet 1 after the image read-out is erased. Thereafter, the sheet 1 is moved reversely in the direction as indicated by the arrow A3 onto a vertically moveable belt conveyor 3a and is conveyed thereby to the stacking section 4. The stacking section 4 shown is constructed not only to stack the sheets 1 but also to sort the sheets 1, for example by the sheet size, into a plurality of stacking trays 4a through vertical movement of the belt conveyor 3a in the direction as indicated by the arrow B.
The aforesaid radiation image read-out apparatus must be constructed compactly so that it may be installed in a small space, and the sheet conveyance system between the respective sections must be adjusted to improve the efficiency of the whole apparatus in view of the conditions at the respective sections.
However, the aforesaid conventional radiation image read-out apparatus in not suitable from the viewpoint of the required installation space or its conveyance system, and should further be improved. Also, particularly, the conveyance system between the read-out section 2 and the erasing section 3 and the conveyance system between the erasing section 3 and the stacking section 4 should be constructed so that the erasing at the erasing section 3 is easy to conduct and no problem arises with the handling of the sheets 1 stacked at the stacking section 4.